Key Laboratory of Luminescence and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
Anal Chem. 2017 Aug 15;89(16):8282-8287. doi: 10.1021/acs.analchem.7b01409. Epub 2017 Aug 2.
In this study, an electrochemiluminescence (ECL) regenerated biosensor was reported to sensitively detect microRNA through 3D DNA walking machine and "on-off-super on" strategy. First, 3D DNA walking machine with higher efficiency of payload releasing and superior signal amplification than those of the traditional DNA walking machine was initially introduced in the ECL system for converting target microRNA to intermediate DNA and achieving significant signal amplification. Second, the distance between CdS:Mn quantum dots and Au nanoparticles was increased with the hybridization of intermediate DNA and Au nanoparticles modified S2, which weakened the energy transfer for ECL signal recovering and excited the surface plasma resonance for further enhancing the signal to construct the on-off-super on biosensor. Such an on-off-super on strategy not only reduced the ECL background signal but also increased the detection sensitivity. Impressively, the elaborately designed biosensor could be regenerated by Lambda exonuclease hydrolyzing the intermediate DNA to make Au nanoparticles modified S2 recover to their original hairpin structure. With the amazing signal amplification of 3D DNA walking machine and sensitive distance control of the on-off-super on strategy, the biosensor showed excellent performance for microRNA-141 detection with a low detection limit of 3.3 fM and could be applied to human prostate cancer cells analysis. Furthermore, this work established a foundation to apply 3D walker in ECL methodology and provided an effective way for analysis of other microRNA or cancer cells.
在这项研究中，报道了一种通过 3D DNA 行走机器和“开-关-超开”策略灵敏检测 microRNA 的电化学发光（ECL）再生生物传感器。首先，引入了效率更高的负载物释放和信号放大能力优于传统 DNA 行走机器的 3D DNA 行走机器，用于将目标 microRNA 转换为中间 DNA，并实现显著的信号放大。其次，中间 DNA 与 Au 纳米粒子修饰的 S2 杂交后，CdS:Mn 量子点和 Au 纳米粒子之间的距离增大，减弱了 ECL 信号恢复的能量转移，并激发了表面等离子体共振，进一步增强了信号，构建了开-关-超开生物传感器。这种开-关-超开策略不仅降低了 ECL 背景信号，还提高了检测灵敏度。令人印象深刻的是，精心设计的生物传感器可以通过 Lambda 核酸外切酶水解中间 DNA 使 Au 纳米粒子修饰的 S2 恢复到其原始发夹结构而实现再生。通过 3D DNA 行走机器的惊人信号放大和开-关-超开策略的灵敏距离控制，该生物传感器对 microRNA-141 的检测表现出优异的性能，检测限低至 3.3 fM，可应用于人前列腺癌细胞分析。此外，这项工作为在 ECL 方法学中应用 3D 行走机器奠定了基础，并为分析其他 microRNA 或癌细胞提供了一种有效的方法。
